1. Field of the Invention
The present invention relates to a chopper circuit and, more particularly, to a chopper circuit that chops the edge of a wave of a received control signal such as a clock, so as to reshape the wave.
2. Description of the Related Art
In the prior art, for example, when a clock signal is used with the waveform thereof left intact, as a designing is required to take account of both the timings of the leading and trailing edges of the clock signal, a chopper circuit (clock chopper circuit) that produces a pulsating signal by detecting the leading edge of the clock signal is necessary.
The employment of the clock chopper circuit obviates the necessity, in design, of taking account of various changes in the timing of the leading edge of a received clock signal. This specification describes a clock chopper circuit as an example of a chopper circuit. Note that the present invention is not limited to a chopper circuit for a clock signal.
Incidentally, Japanese Unexamined Patent Publication (Kokai) No. 55-080136 has proposed, as a clock distribution method for readily and precisely achieving phasing, a method of setting the duty cycle of a clock, which is produced by a clock signal source, to approximately 50%, disposing a wave converter circuit near each load circuit, and applying a distributed clock signal to each of the load circuits via each of the wave converter circuits.
Moreover, Japanese Unexamined Patent Publication (Kokai) No. 07-093999 has proposed as a type of array clock generator circuit, which drives all fast SRAM macros in a system memory whose cycle time is short, a circuit that is realized with a semiconductor chip on which a built-in clock generator that generates two clock waves, one of which lags behind the other (that has chopper circuits set in array so as to produce a plurality of clock signals), is mounted. Herein, the circuit is inspected by performing an array built-in self-test (ABIST) without applying two high-precision clock signals using an expensive tester.
The prior art and its associated problems will be described later with reference to the accompanying drawings.